The executive, Yoshiaki Yamada, who also served as a senior executive managing director of Fuji Television, released a terse statement saying the resignation was unavoidable because he "could not conduct business to my best ability under the circumstances".
Mr Yamada was an intermediary between the two firms which agreed to a limited partnership after Livedoor's bitter and unsuccessful bid for the broadcaster last year. The resignation is seen as a sign that Fuji Television is preparing to cancel the partnership.
Takafumi Horie, Livedoor's president, spent yesterday in his office in Tokyo as investigators questioned his top financial adviser, Ryoji Miyauchi. Livedoor has refused to comment on the investigation since a brief press conference held earlier this week.
Mr Miyauchi is close to Mr Horie and was the prime mover behind Livedoor's most audacious business moves, including its takeover bids for Fuji Television and the baseball team, the Kintetsu Buffaloes. The handsome 38-year-old executive is described across the Japanese media as "the engine of growth" in the company and is suspected by prosecutors of masterminding the alleged share-price scam that has landed the firm in hot water with financial regulators.
An anonymous source on the state broadcaster NHK said Mr Horie, who rarely got involved in business minutiae, relied heavily on his financial director to handle Livedoor's interests. "Horie's job was to sell dreams but Miyauchi was the real mover," the source said.
Investigators are trying to prove Mr Horie knew an investment fund linked to his company concealed its involvement in the takeover of the publisher Value Click to try to drive up the firm's share price. A successful prosecution of Mr Miyauchi would be a serious blow for Mr Horie.
Mr Miyauchi said this week there was "no illegality involved" in the takeover and claimed Mr Horie was "unaware" of the deal.
There was no respite for Livedoor on the Tokyo Stock Exchange yesterday, when Taizo Nishimuro, the president of the exchange, announced that unless the firm clears up doubts about the Value Click incident by the end of the day, it would "very likely" be moved to "monitor status", the prelude to a delisting.
Mr Nishimuro also said the exchange would introduce a computer system at the end of this month to boost its capacity from 4.5 million to 5 million trades a day - an interim measure leading to an eventual upgrade to 8 million. The exchange was forced to pull the plug on trading before the close on Wednesday when it was overwhelmed by sell orders, sparked by the Livedoor scandal.Reuse content